The present invention is directed toward a device for testing for the presence of a specific substance on a surface and, more particularly, toward a small, hand-held dauber which is preimpregnated with a dry powder which, when wetted and rubbed on a painted surface, will indicate the presence of lead in the paint by merely visually observing the dauber.
As is well known in the art, it was common practice at one time for paint manufacturers to incorporate lead in the paint in order to improve the characteristics thereof. When it became apparent, however, that paint chips were being ingested by small children causing brain damage and other defects caused by the lead, lead was banned as an additive for paints. Unfortunately, many homes and other buildings, particularly in the inner cities, continue to have paint on windowsills, frames and walls and the like which contain lead therein and this continues to cause a health hazard.
While many homeowners, landlords and government agencies have removed the lead-based paints from these older buildings, others have simply painted over the old paint with newer, safer paints. Although this provides some measure of protection, it provides no benefit to a small child who may be biting or teething on a windowsill and who may scratch through the top layer of paint to the lead-based paint below. Furthermore, should paint chip off of the painted surface, the paint chips would frequently be comprised of many layers of paint and would, therefore, include lead therein.
Numerous tests have been developed over the years for checking for the presence of lead in painted surfaces. The majority of these require that a paint chip or the like be removed and sent to a laboratory for analysis. Obviously, this is time consuming and, therefore, relatively expensive.
A more convenient, do-it-yourself type test has been developed and is available in the marketplace under the name Lead Check which is sold by Hybrivet Systems, Inc., of Framingham, Mass. This commercially available product includes a hollow, elongated tubular handle having a pair of breakable glass ampules therein. One of the ampules contains a dry powder containing a rhodizonate dye while the other contains an activating solution. An absorbent ball of material such as cotton, felt or the like is mounted at the end of the elongated cylindrical handle. When it is desired to utilize the device, the handle is squeezed or otherwise flexed so as to break the ampules therein. The contents of the ampules mix and are absorbed by the swab ball. The swab can then be rubbed on the painted surface and the presence of lead will be indicated by a red color that appears on the swab. This prior art device is described in U.S. Pat. No. 5,039,618 to Stone.
The Hybrivet test swab has proven to be somewhat useful. However, it is relatively expensive since the ampules must be prepared separately and along with the various other component parts must be assembled to form the finished device. Furthermore, the Hybrivet device can only test for lead on the outermost surface of the paint. Since the device is incapable of scratching beneath the outer surface, it cannot test for lead in an underlayer of paint. There is, therefore, a need for an inexpensive, do-it-yourself type lead tester which is easy to use and which can test for lead beneath the outer surface of the paint.